Revert "f2fs: enhance multi-threads performance"
This reports performance regression by Yuanhan Liu.
The basic idea was to reduce one-point mutex, but it turns out this causes
another contention like context swithes.
https://lkml.org/lkml/2015/4/21/11
Until finishing the analysis on this issue, I'd like to revert this for a while.
This reverts commit 78373b7319abdf15050af5b1632c4c8b8b398f33.
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index b91b0e1..1e1aae6 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1513,6 +1513,7 @@
{
struct inode *inode = mapping->host;
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+ bool locked = false;
int ret;
long diff;
@@ -1533,7 +1534,13 @@
diff = nr_pages_to_write(sbi, DATA, wbc);
+ if (!S_ISDIR(inode->i_mode)) {
+ mutex_lock(&sbi->writepages);
+ locked = true;
+ }
ret = write_cache_pages(mapping, wbc, __f2fs_writepage, mapping);
+ if (locked)
+ mutex_unlock(&sbi->writepages);
f2fs_submit_merged_bio(sbi, DATA, WRITE);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index d8921cf..8de34ab 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -625,6 +625,7 @@
struct mutex cp_mutex; /* checkpoint procedure lock */
struct rw_semaphore cp_rwsem; /* blocking FS operations */
struct rw_semaphore node_write; /* locking node writes */
+ struct mutex writepages; /* mutex for writepages() */
wait_queue_head_t cp_wait;
struct inode_management im[MAX_INO_ENTRY]; /* manage inode cache */
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 160b883..b2dd1b0 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1035,6 +1035,7 @@
sbi->raw_super = raw_super;
sbi->raw_super_buf = raw_super_buf;
mutex_init(&sbi->gc_mutex);
+ mutex_init(&sbi->writepages);
mutex_init(&sbi->cp_mutex);
init_rwsem(&sbi->node_write);
clear_sbi_flag(sbi, SBI_POR_DOING);